How Much Longer Can I Stomach It?

I am still debating as to whether I should go to the doctors or not. I have been suffering with bloating in my stomach almost constantly for about 3 weeks now and have lost my appetite, had severe cramp in my stomach last week, and suffered from diarrhoea twice in the last week! (Too much information? Sorry). But I really don't know what the doctor can do. I hate it when you go to your GP and get that look that they are so good at making, which means "thanks for wasting my time, I really want to get a good, interesting, juicy ailment at some point in my career!"